In Japanese Patent Application Laid-Open No. 9-309492, one example of a water jet propelling type outboard motor is disclosed which pressurizes water which has been drawn from the water by an impeller to jet the same on water surface, thereby obtaining the propelling force.
In a conventional water jet propelling type outboard motor, however, since the entire length of an outboard motor is longer, the center of gravity of a ship is shifted toward the stern of the ship so that the ship is easily put in a state where its bow has been raised. Therefore, the drawback is that straight advancing performance is lowered and meandering occurs easily so that a travelling stability may deteriorate during high speed travelling.
In the outboard motor which has been disclosed in Japanese Patent Application Laid-Open No. 9-309492, water flow rising at the stern of a ship flows in a space formed between a transom board and the outboard motor so that travelling resistance occurs. Also, water flow strikes a lower portion side face of the outboard motor to generate resistance. These resistances negatively impact steering performance.
Japanese Utility Model Application Laid-Open No. 5-65795, discloses an example of a water jet propelling motor provided with forward and rearward moveable screens before and ahead a water suction inlet. The screens prevent floating material such as dust from flowing in the motor through the water suction inlet. By opening the screens, the floating material is captured when the screens are removed due to water flow.
However, a drawback is that when it takes a long time to close the screens, floating material may flow in through the water suction inlet. Also, the inside of the opened rearward screen is subjected to water flow during travelling, and is subjected to contact with floating material. When the rearward screen is closed the floating material attached to the inside of the screen flows in through the water suction inlet. Also, when forward screen moving is closed the floating material becomes trapped between the forward screen and the rearward screen. Accordingly, it is necessary to remove the trapped floating material which is stuck to the screens when the ship stops.